WHEN Prime Minister David Cameron visited Glasgow in July, I interviewed him on the roof of a multi-storey car park next to the SSE Hydro.

He was in the city to announce a multi-million pound investment in infrastructure projects which some politicians described as a pre-referendum bribe.

I put it to the Prime Minister that his party has no Glasgow MPs, and just one MSP and one councillor in the city, and asked if he thought the Scottish Conservatives are popular here.

He hung his head as the wind and rain battered his face on the roof of the car park on the Clydeside and admitted: "We've got work to do to build back the strength of the Conservatives in Scotland."

If Mr Cameron had decided to make his announcement in the nearby SSE Hydro I wonder how many people would have turned out to hear him speak.

On Saturday, four months after the PM's car park press conference, First Minister Nicola Sturgeon spoke at the venue and 12,000 supporters almost took the roof off.

There was dancing in the aisles, punching of the air and stamping of the feet as each senior SNP figure enjoyed a standing ovation.

The rousing speeches were punctuated by stirring songs and swirling bagpipes and elated Nationalists lapped it up.

It was announced at the beginning of the event that SNP membership had swelled to around 90,000.

By the time Nicola Sturgeon arrived on stage it had jumped by another 2000, drawing squeals of delight from the sell-out crowd.

At the end of the event SNP members swarmed around MSPs and MPs to ask for autographs and photographs as if they were the superstars who usually attract such crowds to the venue.

Glasgow MSP Humza Yousaf and his wife, Gail, told me it took them half an hour to get from their seat to the foyer.

Glasgow and Scotland hasn't seen a political rally like it in my adult life.

At the same time Scottish Liberal Democrat leader Willie Rennie and Scottish Secretary Alistair Carmichael were speaking to his party's annual Scottish conference at a 400-seater theatre in Dunfermline.

Nicola Sturgeon couldn't resist joking that the event was being held in a "phone box".

Ed Miliband will be in Glasgow today to speak to supporters at the Royal Concert Hall. The main venue holds 2000 but it is understood he'll be in one of the suites which can seat a maximum of 400.

When the Conservative Prime Minister is holding a press conference in a car park and Labour and Lib Dem leaders meet supporters in small venues while the SNP pack out the Hydro after a crushing defeat, they must be wondering where it all went wrong.